[bootlin/training-materials updates] master: Tinysystem lab: add further work (20fb0d64)

[Michael Opdenacker]

Repository : https://github.com/bootlin/training-materials
On branch  : master
Link       : https://github.com/bootlin/training-materials/commit/20fb0d6455193a79b0cb84054fcb27447ab49e6d

>---------------------------------------------------------------

commit 20fb0d6455193a79b0cb84054fcb27447ab49e6d
Author: Michael Opdenacker <michael.opdenacker at bootlin.com>
Date:   Tue Sep 15 15:55:27 2020 +0200

    Tinysystem lab: add further work
    
    Signed-off-by: Michael Opdenacker <michael.opdenacker at bootlin.com>


>---------------------------------------------------------------

20fb0d6455193a79b0cb84054fcb27447ab49e6d
 labs/sysdev-tinysystem/sysdev-tinysystem.tex | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/labs/sysdev-tinysystem/sysdev-tinysystem.tex b/labs/sysdev-tinysystem/sysdev-tinysystem.tex
index 25649f23..9ecf0e18 100644
--- a/labs/sysdev-tinysystem/sysdev-tinysystem.tex
+++ b/labs/sysdev-tinysystem/sysdev-tinysystem.tex
@@ -292,3 +292,20 @@ opening \code{http://192.168.0.100} on the host.
 
 See how the dynamic pages are implemented. Very simple, isn't it?
 
+\section{Going further}
+
+If you have time before the others complete their labs...
+
+\subsection{Initramfs booting}
+
+Configure your kernel to include the contents of the \code{nfsroot}
+directory as an initramfs.
+
+Before doing this, you will need to create an \code{init} link in the
+toplevel directory to \code{sbin/init}, because the kernel will try to
+execute \code{/init}. You will also need to mount {\em devtmpfs} from
+the \code{rcS} script, it cannot be mounted automatically by the kernel
+when you're booting from an initramfs.
+
+Note: you won't need to modify your \code{root=} setting in the kernel
+command line. It will just be ignored if you have an initramfs.